\begin{table}%t1 \caption{NGC~7538~IRS1 outflow directions reported for various tracers.}\label{tab:tracers} \small%\centerline { \begin{tabular}{l l c c c r c l} \hline\hline Tracer & Structure & Beam size & Scale & PA of & Dynamical & Ref. & Comments\\ & & [\arcsec] & [\arcsec] & outflow & age$^f$ & & (velocities in [\mbox{km~s$^{-1}$}])\\ & & & & direction [$^\circ$] & [$10^3$~yr] & & \\ \hline Methanol masers & & 0.03$^c$ & & +19$^{a,d}$ & -- & [8] & see~Fig.~\ref{fig:speckleimglabel}\\ 1.0~cm cont. & inner core $\la$$0\farcs5$ & 0.13 & 0.4 & +0$^{a}$ & $<$$0.03$ & [9] & $t_{\rm e}=0.15$~yr$^e$\\ 1.3~cm cont. & inner core $\la$$0\farcs4$ & 0.11 & 0.4 & +0$^{a}$ & $<$$0.02$ & [5] & \\ 6.0~cm cont. & inner core $\la$$0\farcs75$ & 0.35 & 0.4 & +0 & $<$$0.04$ & [1] & \\ 1.0~cm cont. & outer core $\ga$$0\farcs5$ & 0.13 & 1.0 & --25$^{a}$ & $>$$0.03$ & [9] & $t_{\rm e}=0.3$~yr$^e$\\ 1.3~cm cont. & outer core $\ga$$0\farcs4$ & 0.11 & 1.0 & --25$^{a}$ & $>$$0.02$ & [5] & \\ 6.0~cm cont. & outer core $\ga$$0\farcs75$ & 0.35 & 1.0 & --15 ... --20 & $>$$0.04$ & [1] & \\ 6.0~cm cont. & outer core $\ga$$0\farcs5$ & 0.4 & 1.0 & --25$^{a}$ & $>$$0.03$ & [9] & \\ MIR $11.7~\mu$m & IRS1~Elongation & 0.43 & 3 & --45 & $0.16$ & [10] & see~Fig.~\ref{fig:mosaic}k\\ MIR $18.3~\mu$m & IRS1~Elongation & 0.54 & 4 & --45 & $0.16$ & [10] & see~Fig.~\ref{fig:mosaic}l\\ NIR ${K'}$-band & IRS1~Elongation & 0.3 & 0.6 & --78 & $0.03$ & -- & see~Fig.~\ref{fig:speckleimglabel}\\ NIR ${K'}$-band & feature~A & 0.3 & 1.6 & --65 & $0.08$ & -- & see~Fig.~\ref{fig:speckleimglabel}\\ NIR ${K'}$-band & feature~F & 0.3 & 2.1 & --33 & $0.11$ & -- & see~Fig.~\ref{fig:speckleimglabel}\\ NIR ${K'}$-band & feature~B & 0.3 & 3.0 & --39 & $0.16$ & -- & see~Fig.~\ref{fig:speckleimglabel}\\ NIR ${K'}$-band & feature~B$'$ & 0.3 & 3.3 & --57 & $0.18$ & -- & see~Fig.~\ref{fig:speckleimglabel}\\ NIR $K'$-band & feature~C & 0.3 & 4.8 & +6 & $0.25$ & -- & see~Fig.~\ref{fig:speckleimglabel}\\ NIR $K'$-band & feature~E & 0.3 & 6.2 & --20 & $0.33$ & -- & see~Fig.~\ref{fig:speckleimglabel}\\ NIR $K'$-band & feature~D & 0.3 & 7.4 & +10 & $0.39$ & -- & see~Fig.~\ref{fig:speckleimglabel}\\ NIR $K'$-band & eastern wall & 0.3 & -- & +25 & -- & -- & see~Fig.~\ref{fig:speckleimglabel}\\ NIR $K'$-band & western wall & 0.3 & -- & -65 & -- & -- & see~Fig.~\ref{fig:speckleimglabel}\\ \FFeII~$1.65$~$\mu$m & & 1 & 15$^a$ & N-S$^{a}$ & $0.8$ & [7] & around IRS2; see~Fig.~\ref{fig:mosaic}i\\ H$_2$ & northern bow & & 30$^a$ & N-S & $1.5$ & [6] & \\ H$_2$ & & 1 & 27$^a$ & --25$^{a}$ & $1.4$ & [7] & shell-like structure; see~Fig.~\ref{fig:mosaic}i\\ H$_2$ & southern bow & & 45$^a$ & 155$^{a}$ & $2.3$ & [6] & see~Fig.~\ref{fig:mosaic}h\\ IRAC bands & southern bow & 1 & 40 & 145 & $2.2$ & -- & see~Fig.~\ref{fig:mosaic}a...e\\ CO & low velocities & 7 & 5$^{a,b}$ & E-W & $0.9$ & [3] & $-11<\tilde{V}_{\rm b}<-6$; $2<\tilde{V}_{\rm r}<9$; see~Fig.~\ref{fig:mosaic}g\\ CO & high velocities & 7 & 15$^{b}$ & -35 & $15$ & [3] & $-17<\tilde{V}_{\rm b}<-11$; $9<\tilde{V}_{\rm r}<15$; see~Fig.~\ref{fig:mosaic}g\\ CO & & 34 & 18$^{b}$ & --50$^{a}$ & $15$ & [2] & $-24<\tilde{V}_{\rm b}<-8$; $9<\tilde{V}_{\rm r}<22$\\ CO & & 16 & 13$^{a,b}$ & --40 & $14$ & [4] & $-14<\tilde{V}_{\rm b}<-9$; $11<\tilde{V}_{\rm r}<16$; see~Fig.~\ref{fig:mosaic}f\\ CO & & 45 & 12$^{a,b}$ & --50$^{a}$ & $10$ & [3] & $-24<\tilde{V}_{\rm b}<-8$; $9<\tilde{V}_{\rm r}<22$\\ \hline \end{tabular}} \medskip Note~--~$\tilde{V}_{\rm r}$ and $\tilde{V}_{\rm b}$ are measured relative to the velocity of methanol maser feature~A ($\tilde{V} = V - 56.25$~km~s$^{-1}$). $^{a}$~Estimated from figures presented within the reference paper; therefore, with limited accuracy; $^{b}$~the half-separation between the red- and blue-shifted CO~lobe is given; $^{c}$~for VLBI observations, we give the estimated error on the absolute position of the measured maser spots; $^{d}$~the expected outflow direction is given; i.e., perpendicular to the measured orientation of maser feature~A; $^{e}$~electron recombination time given in the reference paper; $^{f}$~assuming an outflow velocity of 250~km~s$^{-1}$, which was measured by \citet{gau95} within the H66$\alpha$~recombination line. For the CO~emission, we also use the measured CO~outflow velocity and provide the corresponding dynamical age in brackets. Since all velocities are measured along LOS, this timescale can only provide upper limits.\\ References: [1]~\citet{cam84b}; [2]~\citet{fis85}; [3]~\citet{sco86}; [4]~\citet{kam89}; [5]~\citet{gau95}; [6]~\citet{dav98}; [7]~\citet{blo98}; [8]~\citet{min00}; [9]~\citet{her04}; [10]~\citet{deb05}. \end{table}